Description
Functions for handling events from the window systemDetailed Description
This section describes functions dealing with events from the window system. In GTK+ applications the events are handled automatically in
gtkMainDoEvent and passed on to the appropriate widgets, so these
functions are rarely needed. Though some of the fields in the
Event Structures are useful.Enums and Flags
GdkEventType-
Specifies the type of the event. Do not confuse these events with the signals that GTK+ widgets emit.
Although many of these events result in corresponding signals being emitted,
the events are often transformed or filtered along the way.
nothing- a special code to indicate a null event.
delete- the window manager has requested that the toplevel window be
hidden or destroyed, usually when the user clicks on a special icon in the
title bar.
destroy- the window has been destroyed.
expose- all or part of the window has become visible and needs to be
redrawn.
motion-notify- the pointer (usually a mouse) has moved.
button-press- a mouse button has been pressed.
2button-press- a mouse button has been double-clicked (clicked twice
within a short period of time). Note that each click also generates a
GDK_BUTTON_PRESS event. 3button-press- a mouse button has been clicked 3 times in a short period
of time. Note that each click also generates a
GDK_BUTTON_PRESS event. button-release- a mouse button has been released.
key-press- a key has been pressed.
key-release- a key has been released.
enter-notify- the pointer has entered the window.
leave-notify- the pointer has left the window.
focus-change- the keyboard focus has entered or left the window.
configure- the size, position or stacking order of the window has changed.
Note that GTK+ discards these events for
GDK_WINDOW_CHILD windows. map- the window has been mapped.
unmap- the window has been unmapped.
property-notify- a property on the window has been changed or deleted.
selection-clear- the application has lost ownership of a selection.
selection-request- another application has requested a selection.
selection-notify- a selection has been received.
proximity-in- an input device has moved into contact with a sensing
surface (e.g. a touchscreen or graphics tablet).
proximity-out- an input device has moved out of contact with a sensing
surface.
drag-enter- the mouse has entered the window while a drag is in progress.
drag-leave- the mouse has left the window while a drag is in progress.
drag-motion- the mouse has moved in the window while a drag is in
progress.
drag-status- the status of the drag operation initiated by the window
has changed.
drop-start- a drop operation onto the window has started.
drop-finished- the drop operation initiated by the window has completed.
client-event- a message has been received from another application.
visibility-notify- the window visibility status has changed.
no-expose- indicates that the source region was completely available
when parts of a drawable were copied. This is not very useful.
scroll- the scroll wheel was turned
window-state- the state of a window has changed. See
GdkWindowState
for the possible window states setting- a setting has been modified.
owner-change- the owner of a selection has changed. This event type
was added in 2.6
grab-broken- a pointer or keyboard grab was broken. This event type
was added in 2.8.
gdk-damage- the content of the window has been changed. This event type
was added in 2.14.
GdkEventMask-
A set of bit-flags to indicate which events a window is to receive.
Most of these masks map onto one or more of the
GdkEventType event types
above.
GDK_POINTER_MOTION_HINT_MASK is a special mask which is used to reduce the
number of GDK_MOTION_NOTIFY events received. Normally a GDK_MOTION_NOTIFY
event is received each time the mouse moves. However, if the application
spends a lot of time processing the event (updating the display, for example),
it can lag behind the position of the mouse. When using
GDK_POINTER_MOTION_HINT_MASK, fewer GDK_MOTION_NOTIFY events will be sent,
some of which are marked as a hint (the is_hint member is TRUE).
To receive more motion events after a motion hint event, the application
needs to asks for more, by calling gdkEventRequestMotions.
exposure-mask- receive expose events
pointer-motion-mask- receive all pointer motion events
pointer-motion-hint-mask- see the explanation above
button-motion-mask- receive pointer motion events while any button is pressed
button1-motion-mask- receive pointer motion events while 1 button is pressed
button2-motion-mask- receive pointer motion events while 2 button is pressed
button3-motion-mask- receive pointer motion events while 3 button is pressed
button-press-mask- receive button press events
button-release-mask- receive button release events
key-press-mask- receive key press events
key-release-mask- receive key release events
enter-notify-mask- receive window enter events
leave-notify-mask- receive window leave events
focus-change-mask- receive focus change events
structure-mask- receive events about window configuration change
property-change-mask- receive property change events
visibility-notify-mask- receive visibility change events
proximity-in-mask- receive proximity in events
proximity-out-mask- receive proximity out events
substructure-mask- receive events about window configuration changes of
child windows
scroll-mask- receive scroll events
all-events-mask- the combination of all the above event masks.